Free · Instant calculations
Age Calculator
Calculate completed years, months and days between a birth date and a reference date.
How to use this tool
Choose the calculation method, enter your values and select Calculate. Reset clears results and restores the example inputs.
Formula
Count completed calendar months, then remaining calendar days. Years = whole months ÷ 12.
Example
1 January 1990 to 18 September 2026 is 36 years, 8 months and 17 days.
Assumptions and limits
Dates use calendar days without timezone or daylight saving adjustments. Month-end anniversaries clamp to the last day of shorter months.
Frequently asked question
How are leap-day birthdays handled? In a non-leap year the month-end anniversary falls on 28 February.